Make `Visitor::visit_body` take a plain `&Body`
`ReadOnlyBodyAndCache` has replaced `&Body` in many parts of the code base that don't care about basic block predecessors. This includes the MIR `Visitor` trait, which I suspect resulted in many unnecessary changes in #64736. This reverts part of that PR to reduce the number of places where we need to pass a `ReadOnlyBodyAndCache`.
In the long term, we should either give `ReadOnlyBodyAndCache` more ergonomic name and replace all uses of `&mir::Body` with it at the cost of carrying an extra pointer everywhere, or use it only in places that actually need access to the predecessor cache. Perhaps there is an even nicer alternative.
r? @Nashenas88
Implement -Zlink-native-libraries
This implements a flag `-Zlink-native-libraries=yes/no`. If set to true/yes, or unspecified, then
native libraries referenced via `#[link]` attributes will be put on the linker line (ie, unchanged
behaviour).
If `-Zlink-native-libraries=no` is specified then rustc will not add the native libraries to the link
line. The assumption is that the outer build system driving the build already knows about the native
libraries and will specify them to the linker directly (for example via `-Clink-arg=`).
Addresses issue #70093
Remove `no_integrated_as` mode.
Specifically, remove both `-Z no_integrated_as` and
`TargetOptions::no_integrated_as`. The latter was only used for the
`msp430_none_elf` platform, for which it's no longer required.
r? @alexcrichton
This implements a flag `-Zlink-native-libraries=yes/no`. If set to true/yes, or unspecified, then
native libraries referenced via `#[link]` attributes will be put on the linker line (ie, unchanged
behaviour).
If `-Zlink-native-libraries=no` is specified then rustc will not add the native libraries to the link
line. The assumption is that the outer build system driving the build already knows about the native
libraries and will specify them to the linker directly (for example via `-Clink-arg=`).
Addresses issue #70093
use "gcc" instead of "cc" on *-sun-solaris systems when linking
On illumos and Solaris systems, Rust will use GCC as the link editor.
Rust does this by invoking "cc", which on many (Linux and perhaps BSD)
systems is generally either GCC or a GCC-compatible front-end. On
historical Solaris systems, "cc" was often the Sun Studio compiler.
This history casts a long shadow, and as such, even most modern
illumos-based operating systems tend to install GCC as "gcc", without
also making it available as "cc".
We should invoke GCC as "gcc" on such systems to ensure we get the right
compiler driver.
Rename asm! to llvm_asm!
As per https://github.com/rust-lang/rfcs/pull/2843, this PR renames `asm!` to `llvm_asm!`. It also renames the compiler's internal `InlineAsm` data structures to `LlvmInlineAsm` in preparation for the new `asm!` functionality specified in https://github.com/rust-lang/rfcs/pull/2850.
This PR doesn't actually deprecate `asm!` yet, it just makes it redirect to `llvm_asm!`. This is necessary because we first need to update the submodules (in particular stdarch) to use `llvm_asm!`.
Specifically, remove both `-Z no_integrated_as` and
`TargetOptions::no_integrated_as`. The latter was only used for the
`msp430_none_elf` platform, for which it's no longer required.
Currently, there are three fields in `ModuleConfig` that dictate
how object files are emitted: `emit_obj`, `obj_is_bitcode`, and
`embed_bitcode`.
Some of the combinations of these fields are nonsensical, in particular
having both `obj_is_bitcode` and `embed_bitcode` true at the same time.
Also, currently:
- we needlessly emit and then delete a bytecode file if `obj_is_bitcode`
is true but `emit_obj` is false;
- we needlessly embed bitcode in the LLVM module if `embed_bitcode` is
true and `emit_obj` is false.
This commit combines the three fields into one, with a new type
`EmitObj` (and the auxiliary `BitcodeSection`) which can encode five
different possibilities.
In the old code, `set_flags` would set `obj_is_bitcode` and
`embed_bitcode` on all three of the configs (`modules`, `allocator`,
`metadata`) if the relevant other conditions were met, even if no object
code needed to be emitted for one or more of them. Whereas
`start_async_codegen` would set `emit_obj`, but only for those configs
that need it.
In the new code, `start_async_codegen` does all the work of setting
`emit_obj`, and it only does that for the configs that need it.
`set_flags` no longer sets anything related to object file emission.
Refactor `codegen`
`codegen` in `src/librustc_codegen_llvm/back/write.rs` is long and has complex control flow. These commits refactor it and make it easier to understand.
couple more clippy fixes (let_and_return, if_same_then_else)
* summarize if-else-code with identical blocks (clippy::if_same_then_else)
* don't create variable bindings just to return the bound value immediately (clippy::let_and_return)
Refactorings to get rid of rustc_codegen_utils
r? @eddyb
cc #45276
After this, the only modules left in `rustc_codegen_utils` are
- `link`: a bunch of linking-related functions (many dealing with file names). These are mostly consumed by save analysis, rustc_driver, rustc_interface, and of course codegen. I assume they live here because we don't want a dependency of save analysis on codegen... Perhaps they can be moved to librustc?
- ~`symbol_names` and `symbol_names_test`: honestly it seems odd that `symbol_names_test` is not a submodule of `symbol_names`. It seems like these could honestly live in their own crate or move to librustc. Already name mangling is exported as the `symbol_name` query.~ (move it to its own crate)
I don't mind doing either of the above as part of this PR or a followup if you want.
codegen/mir: support polymorphic `InstanceDef`s
cc #69925
This PR modifies the use of `subst_and_normalize_erasing_regions` on parts of the MIR bodies returned from `instance_mir`, so that `InstanceDef::CloneShim` and `InstanceDef::DropGlue` (where there is a type) do not perform substitutions. This avoids double substitutions and enables polymorphic `InstanceDef`s.
r? @eddyb
cc @nikomatsakis
Remove some imports to the rustc crate
- When we have `NestedVisitorMap::None`, we use `type Map = dyn intravisit::Map<'v>;` instead of the actual map. This doesn't actually result in dynamic dispatch (in the future we may want to use an associated type default to simplify the code).
- Use `rustc_session::` imports instead of `rustc::{session, lint}`.
r? @Zoxc
On illumos and Solaris systems, Rust will use GCC as the link editor.
Rust does this by invoking "cc", which on many (Linux and perhaps BSD)
systems is generally either GCC or a GCC-compatible front-end. On
historical Solaris systems, "cc" was often the Sun Studio compiler.
This history casts a long shadow, and as such, even most modern
illumos-based operating systems tend to install GCC as "gcc", without
also making it available as "cc".
We should invoke GCC as "gcc" on such systems to ensure we get the right
compiler driver.
Optimize catch_unwind to match C++ try/catch
This refactors the implementation of catching unwinds to allow LLVM to inline the "try" closure directly into the happy path, avoiding indirection. This means that the catch_unwind implementation is (after this PR) zero-cost unless a panic is thrown.
https://rust.godbolt.org/z/cZcUSB is an example of the current codegen in a simple case. Notably, the codegen is *exactly the same* if `-Cpanic=abort` is passed, which is clearly not great.
This PR, on the other hand, generates the following assembly:
```asm
# -Cpanic=unwind:
push rbx
mov ebx,0x2a
call QWORD PTR [rip+0x1c53c] # <happy>
mov eax,ebx
pop rbx
ret
mov rdi,rax
call QWORD PTR [rip+0x1c537] # cleanup function call
call QWORD PTR [rip+0x1c539] # <unfortunate>
mov ebx,0xd
mov eax,ebx
pop rbx
ret
# -Cpanic=abort:
push rax
call QWORD PTR [rip+0x20a1] # <happy>
mov eax,0x2a
pop rcx
ret
```
Fixes#64224, and resolves#64222.
Rename rustc guide
This is in preparation for https://github.com/rust-lang/rustc-guide/issues/470
Needs to be merged after we actually rename the guide.
Have used this to rename:
`git grep -l 'rustc_guide' | xargs sed -i 's/rustc_guide/rustc_dev_guide/g'`
`git grep -l 'rustc-guide' | xargs sed -i 's/rustc-guide/rustc-dev-guide/g'`
`git grep -l 'rustc guide' | xargs sed -i 's/rustc guide/rustc dev guide/g'`
This commit modifies the use of `subst_and_normalize_erasing_regions` on
parts of the MIR bodies returned from `instance_mir`, so that
`InstanceDef::CloneShim` and `InstanceDef::DropGlue` (where there is a
type) do not perform substitutions. This avoids double substitutions and
enables polymorphic `InstanceDef`s.
Signed-off-by: David Wood <david@davidtw.co>
panic_bounds_check: use caller_location, like PanicFnLangItem
The `PanicFnLangItem` got switched to using `#[caller_location]` at some point, but `PanicBoundsCheckFnLangItem` was kept in the old style. For consistency, switch that one over to use `#[caller_location]` as well.
This is also helpful for Miri as it means the `assert_panic` machine hook never needs to know the current `Span`.
